1. Field of the Invention
This invention relates to improvements in strand sintering machinery and, in particular, to the drive and alignment apparatus for the pallets and pallet train thereon.
2. Description of the Prior Art
Strand sintering machinery includes an upper trackway made up of parallel rails on which sinter pallets ride. Each pallet is similar to a small cart, usually with four wheels, upon which sinter material reposes and is cooled. The pallet wheels ride on the upper trackway, after receipt of the sintering material, and pass over means for passing cooling air through the sinter material thereon and move toward the discharge end of the machine. At the discharge end of the machine, the pallets move down a sloped section of the parallel rails where the sinter material is emptied by gravity at the apex of an arcuate section of the trackway. The pallets then move, by gravity, further downward and onto a lower trackway. The pallets, at this point, are inverted from their original position on the upper trackway. The inverted pallets, each being pushed in succession by the next pallet in line, move as a pallet train toward the feed end of the machine. At the feed end of the machine a set of gear toothed sprockets engage corresponding gear tooth pockets in each pallet and lift it around a second arcuate section of trackway and drive it forward onto the upper trackway causing it to push its predecessor pallet along the upper trackway in the form of a pallet train.
A major problem inherent in the prior art strand sintering machines is an inability to maintain the pallets in a position parallel to the trackways during the course of the pallets' movements. Several causes have been identified as the source of this problem. One is the fact that the heat that radiates from the sinter material tends to cause movement of the rails. A second is that excess sinter material falls onto the rails causing the pallets to skew. The result of constant misalignment of the pallets with the trackways is excess wear on the pallet wheels and their bearing. The excess wear causes further skewing of the pallets which compounds the problems, resulting in frequent breakdowns and excess maintenance costs.
The gear toothed sprockets tend to realign pallets which are misaligned, but this process causes excess wear on the gear teeth and on the gear tooth pockets of the pallet.
A second problem inherent in prior art strand sintering machines is the tendency of the pallets to stack up or become jammed on the lower trackway preceding the position of the gear toothed sprockets. This causes inordinate pressure on the sprockets resulting in early wear and failure.